1. Field of the Invention
Embodiments described herein relate generally to a fading simulator and a fading simulation method, and more particularly to a fading simulator and a fading simulation method for simulating a radio wave propagation environment associated with, for example, mobile communication terminals, such as cellular phones and mobile terminals.
2. Description of the Related Art
Mobile communication terminals, such as cellular phones, have been rapidly developed in recent years. The radio wave emitted from a base station to a mobile communication terminal is multiplexed by reflection, scattering or diffraction due to land features and the feature of structural objects, and the amplitude and phase of the radio wave randomly vary between different localities. In mobile communication terminals, when receiving radio wave from a base station while moving through a propagation path, fading will occur due to multipath propagation. Communications by the mobile communication terminals are significantly influenced by the fading. Accordingly, to evaluate the communication performance of mobile communication terminals, a device called a fading simulator, which is configured to simulate a radio wave propagation environment, is utilized, as well as a base station simulating device for simulating a base station. Jpn. Pat. Appln. KOKAI Publication No. 2012-195895, for example, discloses a fading simulator.
In conventional fading simulators, a statistical model is usually implemented to estimate the influence of the Doppler effect caused by the movement of a mobile communication terminal. In general, as a statistical model feature, it is desired that no periodicity or reproducibility will occur for a long period of time. In contrast, in practical use of fading simulators, it is desired that the statistical model feature be reliably reproduced or simulated when fading simulation is repeated under the same fading conditions.
However, in the conventional fading simulators, since the reproducibility of the statistical model is not considered, good reproducibility cannot be obtained in a mobile communication terminal test when fading simulation is repeated under the same fading conditions.
An object of the present invention is to provide a fading simulator and a fading simulation method capable of enhancing the reproducibility of a mobile communication terminal test even when fading simulation is repeated under the same fading conditions.